In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?
How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?